찾아보니 npm rebuild node-sass 하거나
nodejs 지웠다가 LTS버전으로 재설치해보시면 될 것 같습니다.
https://stackoverflow.com/questions/37415134/error-node-sass-does-not-yet-support-your-current-environment-windows-64-bit-w
https://medium.com/@proustibat/how-to-fix-error-node-sass-does-not-yet-support-your-current-environment-os-x-64-bit-with-c1b3298e4af0